Catalyst for controlling emissions of the present invention is comprised of at least one kind of transition metal atoms and at least one of Al or Si, wherein said transition metal atoms form a part of the surface of the catalyst for purifying exhaust gas. Accordingly, the catalyst for purifying exhaust gas has both high performance for purifying NO.sub.x and high heat resistance, because monoatomic active metal disperses in the catalyst structure, active metal is taken firmly in the structure, and said transition metal forms a part of the surface of the surface.